SFIC Keymark X4

Small Format Interchangeable Cores (SFIC) are perhaps the most popular style of lock in history. They're so prevalent that nearly every cylinder manufacturer has their own version of a SFIC on the market in effort to capture a piece of the SFIC business. Some of the more elaborate offerings feature patented key control, allowing existing SFIC users to protect against unwanted key duplication without having to replace large amounts of existing hardware. These cylinders have always been limited by the size of the master key systems they can support.